Henry "Harry" Hay, considered by many to be the founder of the modern American gay rights movement, died Thursday at home in San Francisco at age 90.

Born in England in 1912, Mr. Hay grew up with a wealthy real estate investor father who didn't accept his son's homosexuality. In the 1990 biography "The Trouble with Harry Hay," writer Stuart Timmons described how Mr.

Hay's dad beat him and scolded him for not being masculine enough.

In 1919, the family moved to Los Angeles, where Mr. Hay would live most of his life. It was there he learned that intolerance toward gays was widespread.

He became enraged by the treatment gays received in the 1920s and 1930s from police who routinely arrested them for congregating, Timmons wrote.

Mr. Hay got involved in politics and worked for a time as a ghostwriter and actor in Hollywood in the 1930s, where he met his then-partner Will Geer, who later went on to be grandpa on "The Waltons," according to Timmons. Geer introduced Mr. Hay to the Communist Party in the mid-1930s.

During the 1930s, Mr. Hay attended Stanford University but never graduated. He returned to Los Angeles and married Anita Platky -- a fellow Communist -- in 1938. The couple divorced in 1951.

In 1950, Mr. Hay founded the Mattachine Society in Los Angeles. It was the country's first gay rights organization and operated largely underground. Members of the group, which took its name from a French Renaissance folk dance that satirized the elite, swore an oath of anonymity to not reveal their membership or their sexual orientation.

An unabashed Communist, Mr. Hay wrote a manifesto for the group that called for gay liberation at any costs. His stalwart views earned him the moniker the "queer Malcolm X."

He went on to become active in various labor and civil rights causes.

"His death marks the passing of one of the most significant figures in (the gay) struggle for liberation," said Martin Duberman, distinguished professor of history at City University of New York. "He was always out there in defense of the least or most stigmatized members of society. He was a true iconoclast."

In the 1970s, Mr. Hay became more public about his gay activism, forming the gay men's spiritual group, the Radical Faeries. He also authored the collection of essays, "Radically Gay: Gay Liberation in the Words of Its Founder." This year, his life was the subject of an award-winning PBS documentary, "Hope Along the Wind."

But Mr. Hay did not embrace the more recent steps that brought gays openly into the mainstream -- television shows with gay characters, national leaders coming out of the closet and domestic partner benefits at most major companies.

Mr. Hay spoke about how he was uncomfortable with assimilation and mainstream politics. He saw a need to maintain gays' unique contributions to society.

"The assimilationist movement is running us into the ground," he said in a July 2000 Chronicle interview. "Most gay people want to be like everyone else. I frankly have no need to be exactly the same as (San Francisco) Mayor (Willie) Brown."

Mr. Hay and his partner of 39 years, John Burnside, moved to San Francisco in 1999, the same year Mr. Hay was honored as grand marshal in the city's Gay Pride Parade.

Burnside and Mr. Hay's caregivers -- members of the Radical Faeries -- decided he was not getting proper care in Los Angeles and moved him into a home in the Castro district where he was tended to by hospice nurses and received outpatient care for pneumonia and lung cancer.

"His loss and passing occurred in the city he always loved, surrounded by friends and people who loved him," Burnside said. "He was aware his death was coming, and he died in a beautiful way."

"He was one of the first to remind us we need to stop, to consolidate our efforts," said Lyon, who with her partner Del Martin, founded the nation's first lesbian rights organization, the Daughters of Bilitis in 1955. "He was really the originator of the concept of gays, lesbians, bisexuals and transgender people as a minority to be reckoned with."

Joey Cain, president of the San Francisco Pride board of directors and a member of the Radical Faeries, cared for Mr. Hay in the final years of his life. The two met in the 1980s at a retreat.

The younger Cain looked up to Mr. Hay as a mentor and role model.

"He was a hero and I also loved Harry for his mind and wit and for his affection," Cain, 47, said. "He was worried in the final days that he hadn't been successful at the work he set out to do. I told him, 'Harry, honey, you've done the work. Relax. Let go. Other people have taken it up.'

"He was able to feel right about the timing of his death, with the realization that, yes, things had started, things he wanted to accomplish," Burnside said.

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